Replacement Part - CAT40 Tang?

I inadvertently plunged a face mill into a part today and stalled the spindle. Pretty amazing how the inserts survived. Anyway, there are two small tangs on my spindle nose that line up with the CAT40 holder. They are now damaged as a good chunk has sheared off.

What is the purpose of these tangs? Is it simply orientation? I have a deadline tomorrow and I am hoping I can still cut, even if it forces me to perform manual tool changes. Does this piece have a proper name? I can't locate it in the exploded view and parts list for the spindle.

I'd call it a drive lug or drive key. I have made them from 4140 pre-hard. You could make one out of practically anything to get your job out, but I would not harden it, or you'll lose the mechanical fuse capability that you obviously exercised. I would not run long or fast with a substitute without confirming balance issues with the machine maker. My Deckel has one really short drive lug made of heavy alloy (tungsten, I suppose) to balance the long steel lug on the opposite sidekey

Thank you! So it is actually driving? Bummer... looks like it's going to be a long night.

jorsborn said:

I inadvertently plunged a face mill into a part today and stalled the spindle. Pretty amazing how the inserts survived. Anyway, there are two small tangs on my spindle nose that line up with the CAT40 holder. They are now damaged as a good chunk has sheared off.

What is the purpose of these tangs? Is it simply orientation? I have a deadline tomorrow and I am hoping I can still cut, even if it forces me to perform manual tool changes. Does this piece have a proper name? I can't locate it in the exploded view and parts list for the spindle.

View attachment 152266

View attachment 152267

Click to expand...

If you take a look at the tool change flange of the tool holder, assuming the machine has a tool changer, you will see that the cut outs that engage with the drive dogs of the spindle nose (those items that have been broken), are different, necessitating different sized spindle nose drive dogs. This arrangement was made so that the CAT tool holders can be loaded into the spindle in one orientation only and was done so to accommodate proprietary boring cycles, or created conditions where the spindle must stop and orientate so as to be able to move in the opposite direction to the cutting insert to clear a feature when the tool is retracted.

To break the drive dogs, the tool holder must have rotated in the spindle taper to some extent. Accordingly, you should inspect the spindle bore and the Tool Holder taper to see if either are damage, as is frequently the case.

Regards,

Bill

More than likely you have a lot more to be worried about than those drive keys IMHO... Like angelw said above, the tool rotated in the spindle to some extent. Your tram is most definitely gonna be outta wack after that crash.
Have you checked the spindle run-out with a tenth indicator?

Maybe you just got real lucky?

By the way, the only reason I had to make mine was that the used mill came with missing keys, not because I had a bad crash. I've crashed (who hasn't?) but never badly enough to harm the keys or taper.

That is a fadal right? I would make another one out of 4140 and run it. Maybe blue up a tool holder and see if you have damaged the taper. You can get replacements/ rebuilds of fadal spindles fast and cheap.